Is it obligatory to make up for a day of fasting that a man intended to fast in Shawwal, then broke his fast without a valid excuse, after completing the fasting of six days of Shawwal, or is it sufficient for him to have only fasted the six days?

Scholars differed regarding one who began a voluntary fast, whether he is obligated to complete it or not, on two opinions: 1. The first opinion (the preferred one): It is not obligatory to complete a voluntary fast. This is the madhhab of the Shafi’is and Hanbalis. They cited as evidence the hadith of Aisha, that the Prophet, peace and blessings be upon him, broke his voluntary fast when he found food, and other hadiths indicating the permissibility of breaking a voluntary fast without having to make it up. 2. The second opinion: It is obligatory to complete the voluntary fast, and if one breaks it, he must make it up. This is the madhhab of the Hanafis. They cited as evidence the hadith of Aisha, in which it states, "No matter; you two should fast another day in its place," and an addition to the aforementioned hadith of Aisha, "I will fast a day in its place." These additions have been deemed weak.

The preferred opinion is the first one due to the strength of its evidence. Therefore, if a person breaks a voluntary fast, he is not obligated to make up that day.